Soils which have become contaminated with various organic compounds such as oils or pesticides, for example, must be treated to remove the contaminating material in order to prevent the contaminating material from leaching into adjacent areas and ground water. Certain refinery tailings may also contain harmful organic compounds with must be removed before the tailings can be landfilled or otherwise released to the environment.
Organic compounds may be removed from contaminated soil and certain refinery tailings and the like by subjecting the contaminated material to heat. This heat treatment for removing organic compounds is commonly referred to as "thermal stripping." Relatively low temperatures cause light oils and other hydrocarbon contaminants to go into a gaseous phase in which the contaminant releases from the contaminated material. Heavier oils may be driven out of the contaminated material in a gaseous phase at higher treatment temperatures. Even higher temperatures may be used to break chemical bonds in organic compounds such as pesticides, and allow the constituent elements or chemicals to release from the contaminated material. While it has been known to remove organic compounds from contaminated soil and the like through thermal stripping, prior thermal stripping processes have not provided sufficient control to accommodate the many different types of contaminants which may be present in the contaminated soil.